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Re: circuit board makers



Original poster: "Matthew Smith by way of Terry Fritz <twftesla-at-qwest-dot-net>" <matt-at-kbc-dot-net.au>

Hi Ken

>I'm not going to pay to have a circuit board made if  I have to take a hack
>saw to it to give it the "finishing touches." I can make awful, distorted
>crooked boards at home already, and want to do nothing but solder parts to a
>proerly made board.

Saw?  Yuk!  The best thing that I've found for cutting standard glass (FR4) 
board is either sheet metal shears (not tin snips!) or a proper hydraulic 
guillotine.  If you have a friendly local metal fabricator, take 'em a 
scrap of board and get them to cut it for you on a hydraulic guillotine  to 
see what it comes out like.

I use positive photoresist board, which comes covered with a plastic 
tape.  I mark up on the tape and then cut with a standard 12" sheet metal 
shears (terms may differ - there are those who may call this a 
guillotine).  I bought the shears new for just over $100 Australian for 
this very purpose - I took a sample of board into the shop to test before I 
bought.  If you compare this beastie (which can also chop up sheet metal 
quite happily) with a "proper" PCB guillotine, such as sold by Farnell, the 
price comes out to approximately one fifth.

UV exposure boxes can be home-made very easily - the timing mechanism from 
a microwave oven makes a great seconds timer.  Aquarium suppliers are good 
for aerators ("bubble etch") and heaters, whilst a friendly glazier can 
make you up an etching tank to your own specification. Cadsoft's Eagle 
software should more than meet the needs of TCers (free to download), 
although beware the auto-routing function when you're dealing with power - 
others on the list can probably comment better on this.

A final caveat to potential TC PCB makers - although there are some that 
swear by them, I'd say to give both caustic soda (developer) and ferric 
chloride (etchant) a wide berth; I use sodium metasilicate and ammonium 
persulphate respectively.

I managed all this in rural, low-tech South Australia (I'd set it as a 
challenge for myself), and managed to get decent PCB prototyping facilities 
for the equivalent of about $100 US, not including board and chemicals.

Good luck

M

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